There is an interesting feature in Mac OS X we haven’t known about so far: A user has found that the OS lets you run a screen saver showing off your Twitter friends. It is not really an official feature, but rather a programming example that comes with the Leopard developer tools. With few easy steps, users can take the code and turn it into a regular OS X screen saver.
The "hidden Twitter feature" can be found in the Twitterverse Quartz composition: Quartz composition is described be Apple’s developer documentation as a piece of code that processes and renders graphical data - such files are often created without writing a single line of code, but through the Quartz Composer development tool instead. The developer tools on the OS X Leopard DVD include various Quartz composition example files. Twitterverse is one of them.
The "The Twitterverse.qtz" file cannot be executed by itself, but needs to be dragged from the desktop onto the preview in the Screen Saver tab of the Desktop & Screen Saver preference pane available in the System Preferences. Add your Twitter username and password in the screen saver options and you are ready to go. The screen saver will show a wheel with your Twitter friends and their tweets, as illustrated in Thomson’s Flickr stream.